@andypiper Hi,
i just tried with my Sony XB41 loudspeaker.
i launched the pairing on it, i launched a research of BT devices in the pad menu in recalbox, when it was found in the list, i chose my XB41 speaker, it automatically paired.
In the sound menu, you can also find the speaker (or headphones) once it's appaired. Just select it if it's not.